vb_table_get_keys

 get keys in the table.
 [USAGE]
    [keys] = vb_table_get_keys(tbl);
 [IN]
    tbl : table data.
 [OUT]
    keys : key_list  <Nx1 cell>

 Copyright (C) 2011, ATR All Rights Reserved.
 License : New BSD License(see VBMEG_LICENSE.txt)

0001 function [keys] = vb_table_get_keys(tbl)
0002 % get keys in the table.
0003 % [USAGE]
0004 %    [keys] = vb_table_get_keys(tbl);
0005 % [IN]
0006 %    tbl : table data.
0007 % [OUT]
0008 %    keys : key_list  <Nx1 cell>
0009 %
0010 % Copyright (C) 2011, ATR All Rights Reserved.
0011 % License : New BSD License(see VBMEG_LICENSE.txt)
0012 
0013 %
0014 % --- Previous check
0015 %
0016 if ~exist('tbl', 'var')
0017     error('tbl is a required parameter.');
0018 end
0019 
0020 %
0021 % --- Main Procedure
0022 %
0023 keys = [];
0024 if ~isempty(tbl)
0025     keys = {tbl.key};
0026 end